First of all, it's rare for a 6 month old to sleep thru the night. Yes, some babies do, but most do not. As a matter of fact, most toddlers are still not sleeping thru the night.
Personally, I am all for co-sleeping. It is safer than crib sleeping when safety measures are practiced. It was the only way I got any sleep. I could just roll over and nurse and we could both fall back to sleep. It worked great for us. But that doesn't mean it will work for everybody. Rather than transition her back out of your bed, maybe try the side car arrangement. It's where you remove the front of the crib, connect it to your bed so it kinda becomes an extension of your bed. So you can nurse in bed then when baby falls asleep you can scoot her into her own bed. Maybe she will wake up less if she's not so close to you. And yes, the frequent waking may be a habit, but that is not a bad habit. It's what babies, especially breasfed babies, are supposed to do. They wake and want comfort. And nursing is the ultimate comfort. Many moms will tell you to stop that now, that it leads to spoiling. That's garbage. It's normal and it's mother nature at work. And it doesn't last forever. But again, if it's not OK with you, you may want to think about night weaning (which I don't recommend because baby can still get a lot of nourishment over night especially when they become more active during the day). There is also the "don't offer, don't refuse" approach which it seems you are already doing. Meaning you try to sooth her in other ways but then let her nurse when that doesn't work.
I would not increase her solids. There is no proof that increasing solids helps a baby sleep longer. Plus breastmilk is far more nutritious than any solid you can give her and you'll just leave less room in her tummy for the good stuff.
Sounds to me like you are doing all you can do and the best you can do. I think you are doing great with the routine, great on the solids (not too much at this young age), and not refusing to nurse. And BTW, your apprehension about the Ferber method(the cry-it-out approach)is right on! That's your natural mothering instinct telling you to be wary of this tactic. Keep listening to that instinct, mama!
This may just be a phase. She could very easily go right back to sleeping better. And keep in mind any changes you want to see happen should be gradual.
Here are some links you may find helpful:
http://www.mamasource.com/request/8567961257255108609
This is a mom who had similiar sleep problems and you may be interested in the advice she got. Check out the links I gave her, you may be interested in those too. Especially the sleep charts and studies that show how normal frequent waking and night nursing is.
This is an excellent photo demonstration on how to do the side car arrangement:
http://www.freewebs.com/sidecarcrib/index.htm
The Family Bed
This has a ton of even more, excellent links
http://www.kellymom.com/parenting/sleep/familybed.html
Will Giving Formula or Solids at night help baby to sleep longer?
http://www.kellymom.com/nutrition/solids/solids-sleep.html